For a number of years, there have been schemes for blocking undesired incoming telephone calls based on access codes. An access code is a number that performs a function similar to the combination to a lock. With these existing schemes, when a caller calls a destination phone, the destination phone answers the call and asks the caller to enter an access code. The caller enters the access code from the caller's keypad. Undesired callers are blocked because those callers know the destination phone's phone number, which is widely distributed, but do not know the access code, which is secret.
A problem with such schemes is that for each phone, there is only one access code. Eventually this access code also becomes widely distributed and falls into the hands of undesired callers. Because there is only one access code, it is not possible to block incoming calls from one undesired caller without also blocking calls from all callers. A solution to this problem is well known. It is to use multiple access codes for each phone. Whenever the owner of a telephone is asked for his or her phone number, he or she gives out his phone number along with a unique access code. If one access code falls into the hands of an undesired caller, the owner of the telephone disables only that one access code.
There are a number of problems associated with multiple access codes. One problem relates to the face that an owner of the telephone must be able to produce a unique access code whenever and wherever he or she is asked for his or her telephone number. Another problem is that after creating a new access code, the owner must manually keep track of the access code. At a minimum, the owner must manually keep track of the access code for as long as it takes to enter the access code into an automated database. Since the owner of a telephone is frequently not near a computer terminal, this is difficult.
As such, what is needed is a solution that overcomes these problems and limitations by providing a mechanism for blocking undesired phone calls, e-mail messages, or presence subscription requests.